Blood transfusion is a well known therapeutic process. The purpose of a transfusion is to provide blood component(s) that will improve the physiological status of a patient. Various blood components can be harvested from a single donation of whole blood. Most blood banks are able to separate red cells and plasma components. Others are able to prepare components such as platelet concentrates and cryoprecipitate. Whole blood and/or its components are typically stored in blood bags.
The collection of blood from donors may take place within a blood transfusion center or hospital blood bank. Blood is also often collected from donors during mobile blood collection sessions. The blood is then taken to a laboratory for testing and processing into components and for storage and distribution as the need arises.
Blood is collected at body temperature, i.e. +37° C. But in order to maintain its vital properties, it must be cooled to below +10° C. to be transported, and stored at refrigeration temperatures of around +4° C. until use. If blood is stored or transported outside of these temperatures for long periods of time, it loses its ability to transport oxygen or carbon dioxide to and from tissues respectively upon transfusion. Other factors of serious concern are the risk of bacterial contamination if blood is exposed to warm temperatures.
More specifically, whole blood and red cells must always be stored at a temperature between +2° C. and +6° C. If blood is not stored at between +2° C. and +6° C., its oxygen-carrying ability is greatly reduced. Another important reason for storing blood between +2° C. and +6° C. is to keep the growth of any bacterial contamination in the unit of blood to a minimum. If blood is stored above +6° C., bacteria that may have inadvertently entered the unit during collection may grow to such an extent that transfusion of the contaminated blood could be fatal. The lower limit of +2° C. is also very important. This is because red cells are very sensitive to freezing. If they are allowed to freeze, the red cell membranes rupture and the hemoglobin is released; that is, the cells are hemolysed. The transfusion of hemolysed blood can also be fatal.
Fresh frozen plasma (FFP) is plasma that has been separated from a unit of whole blood within 6 to 8 hours of collection, and has been rapidly frozen and maintained at all times at a temperature of −20° C. or lower. There is no lower temperature limit for the storage of FFP, although the optimal temperature is −30° C. or lower.
Plasma contains water, electrolytes, clotting factors and other proteins (mostly albumin), most of which are stable at refrigerator temperature, i.e. +2° C. to +6° C. Factor V and Factor VIII, however, which are essential in the clotting mechanism, will deteriorate and diminish in quantity if they are not stored at −20° C. or lower and greatly reduce the clotting activity of the plasma. FFP may be given to a patient to restore or help to maintain coagulation factors such as Factor V or Factor VIII.
Cryoprecipitate is the cold insoluble portion of plasma remaining after FFP has been thawed between +1° C. and +6° C. and is useful for correcting certain coagulation defects. It contains approximately 50% of Factor VIII and von Willebrand Factor, 20-40% of fibrinogen and some of the Factor XIII originally present in the fresh plasma.
Plasma is separated from red cells within 6 to 8 hours of collecting blood. The plasma is frozen solid rapidly, certainly within 30 minutes of separation from the cells. The plasma is then thawed slowly at below +4° C. In order to obtain the maximum yield of Factor VIII in the cryoprecipitate from a blood unit it is important to adhere strictly to standard procedures for the collection, storage and processing of the component. The stability on storage is dependent on the storage temperature available. The optimal storage temperature is below −30° C.
In view of these requirements, whole blood and packed red cells must be stored at +2° C. to +6° C. and transported between +2° C. and transported between +2° C. to +10° C. The optimal storage temperature for fresh frozen plasma and cryoprecipitate is −30° C., and they must always be frozen solid.
Blood bags containing whole blood and/or blood components are typically labeled. Current practice employs origination labels that are affixed to a blood bag which identifies its origin, contents, date, and other items. These labels remain attached to the blood bags during cold storage and up to and during the time at which the blood bag is removed from cold storage and allowed to thaw or increase in temperature prior to use.
At some point prior to accessing the contents of a blood bag, typically current practice involves attaching one or more supplemental labels to the blood bag. Typically, the supplemental label is placed on the origination label. These supplemental labels include information concerning the patient or intended recipient of the blood or blood component. A problem frequently encountered is that the blood bags, having recently been removed from cold storage, contain condensation or a layer of frost or ice crystals (depending upon the temperature of the bag) along the outer surface of the bag and label. This layer of condensation or frost significantly interferes with application of supplemental labels to the blood bags, and particularly to an outer face of the origination label.
Thus, prior to application of a supplemental label, a medical practitioner must wipe away any moisture or frost residing in the region of supplemental label application. As will be appreciated, this is undesirable particularly when in an emergency situation. Furthermore, even if wiping or other efforts are performed, in many instances moisture still remains along the bag and label outer face which can interfere with application of one or more supplemental labels. In view of this, it will be appreciated that an alternative labeling strategy is needed.
A wide array of other articles and products are known which are subjected to some type of cold storage and then after being removed from the cold environment are warmed to some degree. It is frequently desirable to apply a label to the articles or products after removal from the cold environment. These articles or products are also susceptible to formation of condensation or frost along their outer surface. As previously explained, such condensation or frost interferes with labeling. Accordingly, new strategies are needed for labeling such goods.